Effect of Antimicrobial Peptide from Marine Microorganism on the Storage Quality of Freshly Squeezed Cucumber Juice

To investigate the effects of different concentrations of antimicrobial peptide from marine Bacillus subtilis on the quality changes of freshly squeezed cucumber juice during the storage period (5 d) at room temperature. Sensory evaluation, physicochemical analysis (pH, stability coefficient, total sugar content, total bacteria count), and electronic nose technique (principal component analysis, radar plot, corresponding values of primary flavor components sensors) were used to comprehensively evaluate the effect of freshness preservation. The results showed that the concentration of antimicrobial peptide was positively correlated with various physicochemical indexes. And 2×MIC concentration of antimicrobial peptide had the best effect, with the highest sensory score (7.03), pH (4.97), stability factor (32.86%), total sugar content (5.11 mg/mL), and the best antibacterial effect (0.88 log CFU/mL). Principal component analysis (PCA) showed that the flavor characteristics of cucumber juice in each antimicrobial peptide treatment group were similar, while the flavor characteristics of cucumber juice in the control group and the potassium sorbate treatment group were similar. The radar plot revealed that the flavor components of cucumber juice in each antimicrobial peptide treatment group increased at the later stage of storage (5th d), while the flavor components of cucumber juice in the control and potassium sorbate treatment groups remained unchanged basically during the storage period. The analysis of the response values of the flavor component sensors showed that the antibacterial peptide from Bacillus subtilis BBW1542 had a certain impact on the volatile flavor compounds in freshly squeezed cucumber juice. In conclusion, the preservation effect of antimicrobial peptide from B. subtilis BBW1542 was significantly better than that of the chemical preservative group (P<0.05). This study would provide a theoretical basis for the quality assurance of freshly squeezed cucumber juice in short-term storage and the development of marine microbial freshness preservatives.